Name ______Date ______

Chapter 12 – Kinetics Review Test

2) Consider the reaction: 4NH3 + 7O2 4NO2 + 6H2O. At a certain instant the initial rate of disappearance of the oxygen gas is X. What is the value of the appearance of water at the same instant?

A)1.2 X

B)1.1 X

C)0.86 X

D)0.58 X

E)cannot be determined from the data

3) Which of the following is needed to determine the rate law for a reaction?

I. Balanced equation

II. experimentation

III. graphical analysis

A) III only

B) I & II only

C) II & III only

D) I & III only

E) I, II, & III

Use the following experiment to answer questions 5 & 6.

Tabulated below are initial rate data for the reaction

2Fe(CN)63– + 2I–  2Fe(CN)64– + I2

Initial

Run[Fe(CN)63–]0 [I–]0[Fe(CN)64-]0 [I2] 0Rate (M/s)

10.01 0.010.01 0.011 x 10–5

20.01 0.020.01 0.012 x 10–5

30.02 0.020.01 0.018 x 10–5

40.02 0.020.02 0.018 x 10–5

50.02 0.020.02 0.028 x 10–5

5) The experimental rate law is:

A) rate = k[Fe(CN)63–]2[I–]2[Fe(CN)64–]2[I2]

B) rate = k[Fe(CN)63–]2[I–][Fe(CN)64–][I2]

C) rate = k[Fe(CN)63–)]2[I–]

D) rate = k[Fe(CN)63–][I–]2

E) rate = k[Fe(CN)63–][I–] [Fe(CN)64–]

6) The value of k is:

A)107 M–5 s–1

B)103 M–3 s–1

C)10 M–2 s–1

D)50 M–2 s–1

E)none of these

Use the following experiment to answer questions 7- 11

A general reaction written as 2A + 2B  C + 2D is studied and yields the following data:

[A]0[B]0Initial D[C]/Dt

0.100 M0.100 M0.000040 mol/L × s

0.200 M0.100 M0.000160 mol/L × s

0.100 M0.200 M0.000040 mol/L × s

7) What is the order of the reaction with respect to B?

A)1

B)4

C)3

D)2

E)0

8) What is the overall order of the reaction?

A)1

B)4

C)3

D)2

E)0

9) What are the proper units for the rate constant for the reaction?

A)s–1

B)M–1 s–1

C)M1 s–1

D)M–3 s–1

E)M–2 s–1

10) What is the numerical value of the rate constant?

A)0.000040

B)0.000160

C)0.0040

D)0.0160

E)4.0 x 10–7

11) For the first of the reactions in the table of data, how many seconds would it take for [A] to decrease to 0.050 M?

A)1200

B)1700

C)170

D)2500

E)250

12) Consider the following data concerning the equation:

H2O2 + 3I– + 2H+ I3– + 2H2O

[H2O2] 0 [I–]0[H+]0rate

I.0.100 M 5.00 × 10–4 M1.00 × 10–2 M0.137

II.0.100 M 1.00 × 10–3 M1.00 × 10–2 M0.268

III.0.200 M 1.00 × 10–3 M1.00 × 10–2 M0.542

IV.0.400 M 1.00 × 10–3 M2.00 × 10–2 M1.084

Two mechanisms are proposed:

I.H2O2 + I– H2O + OI–

OI– + H+ HOI

HOI + I– + H+ I2 + H2O

I2 + I– I3–

II.H2O2 + I– + H+ H2O + HOI

HOI + I– + H+ I2 + H2O

I2 + I– I3–

Which of the following describes a potentially correct mechanism?

A) Mechanism I with the first step the rate determining step.

B) Mechanism I with the second step the rate determining step.

C) Mechanism II with the first step rate determining.

D) Mechanism II with the second step rate determining.

E) None of these could be correct.

14) The rate expression for a particular reaction is rate = k[A][B]2. If the initial concentration of B is increased from 0.1 M to 0.3 M, the initial rate will increase by which of the following factors?

A)2

B)6

C)12

D)3

E)9

15) The following data were collected for the decay of HO2 radicals:

Time[HO2]

0 s1.0 x 1011 molec/cm3
2 s5.0 x 1010 molec/cm3

6 s2.5 x 1010 molec/cm3

14 s1.25 x 1010 molec/cm3

30 s6.225 x 109 molec/cm3

Which of the following statements is true?

A) The decay of HO2 occurs by a first-order process.

B) The half-life of the reaction is 2 ms.

C) Plot of ln [HO2] versus time is linear with a slope of –k.

D) The rate of the reaction increases with time.

E) A plot of 1/[HO2] versus time gives a straight line.

Use the following experiment to answer questions 20 – 22.

For the reaction 2N2O5(g)  4NO2(g) + O2(g), the following data were collected:

t (minutes)[N2O5] (mol/L)

01.24 x 10–2

10.0.92 x 10–2

20.0.68 x 10–2

30.0.50 x 10–2

40.0.37 x 10–2

50.0.28 x 10–2

70.0.15 x 10–2

20) The order of this reaction in N2O5 is

A)0

B)1

C)2

D)3

E)none of these

21) The concentration of O2 at t = 10. minutes is

A)2.0 x 10–4 mol/L

B)0.32 x 10–2 mol/L

C)0.16 x 10–2 mol/L

D)0.64 x 10–2 mol/L

E)none of these

Use the following experiment to answer questions 23 – 25.

The reaction A  B + C is known to be zero order in A with a rate constant of5.0 x 10–2 mol/L × s at 25°C. An experiment was run at 25°C where [A]0 = 1.0 x 10–3 M.

23) The integrated rate law is

A)[A] = kt

B)[A] – [A]0 = kt

C)[A]/[A]0 = kt

D)ln[A]/[A]0 = kt

E)[A]0 – [A] = kt

24) After 5.0 minutes, the rate is

A)5.0 x 10–2 mol/L × s

B)2.5 x 10–2 mol/L × s

C)1.2 x 10–2 mol/L × s

D)1.0 x 10–3 mol/L × s

E)none of these

25) The half-life for the reaction is

A)1.0 x 10–2 s

B)1.0 x 102 s

C)5.0 x 10–2 s

D)5.0 x 10–4 s

E)none of these

26) Determine the molecularity of the following elementary reaction: O3 O2 + O.

A)unimolecular

B)bimolecular

C)termolecular

D)quadmolecular

E)the molecularity cannot be determined

Use the following experiment to answer questions 27 – 28.

The following questions refer to the reaction 2A2 + B2 2C. The following mechanism has been proposed:

step 1 (very slow)A2 + B2 R + C

step 2 (slow)A2 + R  C

27) What is the molecularity of step 2?

A)unimolecular

B)bimolecular

C)termolecular

D)quadmolecular

E)the molecularity cannot be determined

28) Which step is "rate determining"?

A)both steps

B)step 1

C)step 2

D)a step that is intermediate to step 1 and step 2

E)none of these

29) If a reaction is zero order, which of the following will yield a linear plot?

A)log [HI] vs time

B)1/[HI] vs time

C)[HI] vs time

D)ln [HI] vs time

30) The reaction 2A + B  C has the following proposed mechanism:

Step 1: A + B  D (fast equilibrium)

Step 2: D + B  E

Step 3: E + A  C + D

If step 2 is the rate-determining step, then the rate of formation of C should equal:

A)k[A]

B)k[A]2[B]

C)k[A]2[B]2

D)k[A][B]

E)k[A][B]2

31) The reaction 2NO + O2 2NO2 obeys the rate law

Rate = k[NO]2[O2]

Which of the following mechanisms is consistent with the experimental rate law?

A) NO + NO  N2O2(slow)

N2O2 + O2 2NO2(fast)

B) NO + O2 NO3(fast equilibrium)

NO3 + NO  2NO2(slow)

C) 2NO N2O2(fast equilibrium)

N2O2 NO2 + O(slow)

NO + O  NO2(fast)

D) O2 + NO  NO2 + O(slow)

O + NO  NO2(fast)

E) none of these

32) The reaction 2H2O2 2H2O + O2 has the following mechanism?

H2O2 + I– H2O + IO–

H2O + IO– H2O + O2 + I–

The intermediate species in the reaction is:

A)H2O

B)I–

C)H2O2

D)IO–

34) The catalyzed pathway in a reaction mechanism has a ______activation energy and thus causes a ______reaction rate.

A)higher, lower

B)higher, higher

C)lower, higher

D)lower, steady

E)higher, steady

35) The rate constant k is dependent on

I. the concentration of the reactant.

II. the nature of the reactants.

III. the temperature.

IV. the order of the reaction.

A)none of these

B)one of these

C)two of these

D)three of these

E)all of these

6)

a) Is the rxn exo or endo thermic? Explain.

b) At what point on the graph is the activated complex present?

c) If the reaction were reversible, would the forward or the reverse reaction have a higher activation energy?

d) Which letter shows the activation energy?

e) Which letter shows the change in energy for the overall reaction?

f) Which letter shows the activation energy using a catalyst?

Answer to the multiple choice: 2c 3c 5c 6c 7e 8d 9b 10c 11d 12a 14e 15e 20b 21c 23e 24a 25a 26a 27b 28b 29c 30e 31b 32d 34c 35c

Answer to Free response

a) endo because the energy of the products is higher than that of the reactants thus energy was added to the system

b) at the top of the hill above the c line.

c) forward, greater distance between “reactants” and activation energy, thus more energy required.

d) a

e) d

f) e